This invention relates to a valve timing control apparatus for an internal combustion engine which is configured to control opening and closing characteristics of an intake valve and an exhaust valve which are engine valves of the internal combustion engine, and a controller for the valve timing control apparatus.
In recent years, in a valve timing control apparatus arranged to vary valve timings of engine valves, there is a demand that a relative rotational position of cam shaft with respect to a timing sprocket is controlled in a retard angle direction and in an advance angle direction in accordance with an engine driving state, in addition to a valve timing which is optimum for a start of the engine.
Moreover, in a lift varying apparatus to vary a valve lift amount of an engine valve, there is a demand that the valve lift amount is increased or decreased with respect to the valve lift amount which is optimum for the start of the engine.
At the start of the engine, the valve timing of the intake valve needs to be held at an intermediate phase position between the most retarded angle position and the most advance angle position. Japanese Patent Application Publication No. 2004-156508 discloses a valve timing control apparatus arranged to control to the intermediate phase position which is optimum for the start of the engine.